VIM: Know which command executed when a key pressed

Question

How do I know which command will be executed when I press a key, for example <Leader>c?

Answer 1

To see mappings use:

:verbose map <leader>c

Replace map by the corresponding imap, cmap, etc., as needed.

For Vim's built-in commands you'll need to use the help:

:help gq

See :help context for pointers.

Answer 2

Sometimes if map <keys> is not enough you may use one of the following:

• :debug normal <keys><CR>: for normal, visual, select, operator-pending and insert/replace/virtual replace modes but not for ex/command-line mode. You will have to precede <keys> with something that enters target mode.
• :set verbosefile=/tmp/verbose.log verbose=15<CR><keys>:set verbose=0<CR>: for all modes it will procude a log of all commands executed in file /tmp/verbose.log. You will see errors if there is a recursive structure somewhere.
• Start vim with vim -s <(echo '<keys>') -D. It will enter debug mode immediately after vim starts, but you will have to skip all initializations manually.

These are all advanced debugging features and they are very time-consuming, but they may help where something more simple cannot.